An electron microscopic study of penetration by Trypanosoma rangeli into midgut cells of Rhodnius prolixus

The process of interaction of the Choachi strain of Trypanosoma rangeli wit h intestinal epithelial cells of Rhodnius prolixus was analyzed in experime nts carried out in vitro and in vivo, For the in vitro experiments small fr agments of the anterior region of the posterior midgut were incubated in th e presence of the parasites, fixed, and processed for observation with the scanning electron microscope, Parasites attached to the surface of some epi thelial cells, especially to the extracellular membrane layers (perimicrovi llar membranes), were observed, For the in vivo experiments insects were in fected with cultures of T, rangeli, sacrificed at different time intervals, and then processed for scanning and transmission electron microscopy, An i ntimate contact between the parasites and the membrane layers was observed, The parasites penetrated into cells that showed an electronlucent cytoplas m and a damaged surface, moved within the cytoplasm of the epithelial cell, reached the basal region, crossed the basal lamina, and entered the hemoco el, (C) 2001 Academic Press.